The present invention relates to lubricating devices, more particularly to a lubrication device that can be used, for example, to lubricate a wheel flange of a railway vehicle.
On a railway wheel, a distinction is made between the generally tapered rolling surface in contact with the top surface of the rail and the wheel flange. The wheels are guided on the rails in a straight line by the tapered nature of the rolling surfaces and in the curves by the wheel flange which bears on the lateral faces of the rail. The wheel flange exceeds the rolling surface by a number of centimeters, and prevents any risk of the transit car being derailed. The friction forces between the wheel flange and the lateral surface of the rail result in wear of the flange, energy losses through friction and noise.
In order to reduce these drawbacks, lubrication devices are generally provided which deposit lubricant on the wheel flange or on the lateral faces of the rails by spraying a jet of lubricant.
Current lubrication devices typically use compressed air mixed with a lubricant, this mixture being sprayed in the form of a jet produced through the intermediary of a nozzle positioned in the vicinity of the wheel flange. Such devices are, for example, described in U.S. Pat. Nos. 3,760,904 and 6,186,411. These lubrication devices increase the storage volumes needed to compress the air, which makes the air compressors installed on the motor coaches and used for other equipment relatively costly. Moreover, they do not allow the quantity of lubricant sprayed onto the wheel flange to be delivered accurately because of the non-uniform nature of the air-lubricant mixture.
Another type of lubrication device described in patent of invention BE 893171 comprises an electromagnetic pump which directly sprays the lubricant onto the flange without compressed air, which allows this pump to deliver the quantity of lubricant sprayed onto the flange with accuracy. By providing an inlet valve and an outlet valve actuated in time in a deferred manner, this pump makes it possible to suck the lubricant into a chamber and to discharge it under pressure. Nevertheless, this pump does not make it possible to spray an adequate jet of lubricant onto the wheel flange because of the viscosity of the lubricant and the path the lubricant follows in the lubrication device. Such a pump is not suited to all types of lubricant and to the variations in outside temperatures that range, for example, in certain circumstances, between −30° C. and +50° C., which alters the viscosity of the lubricant, making an accurate adjustment of the quantity of lubricant sprayed very difficult.